Fuji Electric ALPHA7, User Manual

Page: 550 / 662

CHAPTER 13 MODBUS RTU COMMUNICATION
Transmission Protocol
13-11
13
 FC 01h (Read out coil data)
(1) Query from the master
Station No. 1 byte
FC 1 byte ･･･
01h
Information
Address 2 bytes
(H)
･･･
Specify the coil address.
* For the addresses, refer to the table 13-2.
(L)
No. of coil data 2 bytes
(H)
･･･
Specify the number of coils n.
* Up to 16 pcs.
(L)
CRC check
16 bits
(2 bytes)
(L)
(H)
(2) Response message form the amplifier
Station No. 1 byte
FC 1 byte
･･･
01h
Information
No. of data bytes 1 byte
･･･
The value (N) obtained from n/8 and by
rounding up decimal
Data 1 1 byte (8 bits)
･･･
n pcs data read out from a specified address.
* 1 pcs = 1 bit (1 byte by 8 pcs)
* Allocated from LSB in order.
~
~
Data N 1 byte (8 bits)
CRC check
16 bits
(2 bytes)
(L)
(H)
(3) Message examples
Shows a message example to read out ten pieces of coil data from OUT6 signal.
<Query example>
Station No. 1 byte 01 ･･･
When the amplifier station no. is "1".
FC 1 byte 01
Information
Address 2 bytes
03 ･･･
Specify 0305h as the OUT6 signal address.
05
No. of coil data 2 bytes
00
･･･
Specify 10 = 000Ah as the number of coils.
0A
CRC check
16 bits
(2 bytes)
AC
48
<Response message example>
Station No. 1 byte
01
FC 1 byte 01
Information
No. of data bytes 1 byte 02
･･･
The value obtained from 10 pcs/8 and by
rounding up decimal
Data 1 1 byte A5
･･･
See below.
Data 2
1 byte 02
CRC check
16 bits
(2 bytes)
43
6D
Data are allocated from LSB in order starting from the smaller address.
The corresponding bit indicates ON with "1" and OFF with "0". The rest of bits are all fixed to "0."